Vane pump

ABSTRACT

A vane pump includes a pump rotor having a through hole to which a driving shaft is coupled, a pump housing configured to accommodate the pump rotor and the cam ring, and a first side plate provided between the pump rotor and a bottom surface of the pump housing. The first side plate or the pump housing is formed with a projection, the projection is inserted into the through hole of the pump rotor.

TECHNICAL FIELD

The present invention relates to a vane pump.

BACKGROUND ART

JP2013-136965A discloses an electric vane pump including an electricmotor and a vane pump that is driven by a motive force from the electricmotor.

SUMMARY OF INVENTION

The electric vane pump disclosed in JP2013-136965A may be produced byassembling the electric motor and the vane pump after the electric motorand the vane pump have been fabricated separately. In such a case, theelectric motor and the vane pump are assembled by inserting a shaft ofthe electric motor into a through hole of a rotor of the vane pump.

However, because the rotor of the vane pump is in a freely movable statein a cam ring, an operation of inserting the shaft of the electric motorinto the through hole of the rotor of the vane pump is complicated.Especially, when the vane pump and the electric motor are assembled in astate in which the diameter of the rotor is orientated so as to coincidewith the vertical direction, the rotor falls into a bottom portion inthe cam ring and the centers of the rotor and the cam ring are deviatedgreatly, and therefore, an operation of inserting the shaft of theelectric motor into the through hole of the rotor of the vane pumpbecomes further complicated.

An object of the present invention is to improve assemblability of avane pump.

According to one aspect of the present invention, a vane pump includes:a rotor having a through hole to which a driving shaft is coupled; aplurality of vanes provided so as to be freely reciprocatable in aradial direction with respect to the rotor; a cam ring configured toaccommodate the rotor, the cam ring being configured such that tip-endsof the vanes slide on an inner circumferential surface of the cam ringas the rotor is rotated; a housing configured to accommodate the rotorand the cam ring; and a side plate provided between the rotor and abottom surface of the housing. The side plate or the housing is formedwith a projection, the projection being inserted into the through holeof the rotor.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view of a vane pump according to a firstembodiment of the present invention.

FIG. 2 is a diagram showing a state before an electric motor and thevane pump are assembled.

FIG. 3 is a sectional view of the vane pump according to a modificationof the first embodiment of the present invention.

FIG. 4 is a side view of a first side plate.

FIG. 5 is a sectional view of the vane pump according to a secondembodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will be described below withreference to the drawings.

First Embodiment

A vane pump 100 according to a first embodiment of the present inventionwill be described with reference to FIG. 1.

The vane pump 100 is, for example, used as a hydraulic pressure sourcefor supplying working oil (working fluid) to a hydraulic apparatus, suchas a continuously variable transmission, etc., mounted on a vehicle.

The vane pump 100 is driven by a motive force from an electric motor 1.The vane pump 100 is coupled coaxially to the electric motor 1 via adriving shaft 4.

The electric motor 1 includes the driving shaft 4 that is rotatablysupported by a motor housing 3 via bearings 2 a and 2 b, a motor rotor 5that has a plurality of permanent magnets arranged in thecircumferential direction and that is fixed to the driving shaft 4, anda stator 6 that is fixed to an inner circumference of the motor housing3 and that is formed by winding a coil. The motor rotor 5 and the stator6 are arranged concentrically, and there is a small gap between themotor rotor 5 and the stator 6.

The motor housing 3 includes a main body portion 3 a having a partiallybottomed cylinder shape and a motor cover 3 b that closes an openingportion of the main body portion 3 a. The vane pump 100 is connected tothe motor cover 3 b. The main body portion 3 a and the motor cover 3 bare assembled integrally by fitting an annular fitting portion 3 cformed in the motor cover 3 b into an inner circumferential surface ofthe main body portion 3 a.

The bearing 2 a is fixed to a bottom portion of the main body portion 3a, and the bearing 2 b is fixed to an inner circumferential surface of ahollow portion 3 d of the motor cover 3 b. The driving shaft 4 isrotatably supported by two bearings 2 a and 2 b and is provided so as toextend by being inserted through the hollow portion 3 d of the motorcover 3 b. As described above, the driving shaft 4 is configured not asa part of the vane pump 100, but as a part of the electric motor 1.

The vane pump 100 includes a pump rotor 31 that is coupled to thedriving shaft 4, a plurality of vanes 32 that are provided so as to befreely reciprocatable in the radial direction with respect to the pumprotor 31, a cam ring 33 that accommodates the pump rotor 31 and has aninner circumferential cam face on which tip-ends of the vanes 32 slideas the pump rotor 31 is rotated, and a pump housing 40 that accommodatesthe pump rotor 31 and the cam ring 33.

The driving shaft 4 is supported only by the bearings 2 a and 2 bprovided in the electric motor 1, and a bearing for supporting thedriving shaft 4 is not provided in the vane pump 100. A male spline 4 ais formed on an outer circumferential surface of an end portion of thedriving shaft 4 on the vane pump 100 side.

The pump rotor 31 is an annular member, and a through hole 31 a, throughwhich the driving shaft 4 is inserted, is formed at the center portionof the pump rotor 31 so as to penetrate therethrough in the axialdirection. A female spline 31 b is formed on an inner circumferentialsurface of the through hole 31 a (see FIG. 2), and the male spline 4 aof the driving shaft 4 meshes with the female spline 31 b. As describedabove, the driving shaft 4 is coupled to the pump rotor 31 with a splineconnection. In FIG. 1, illustration of the female spline 31 b isomitted.

In the cam ring 33, a plurality of pump chambers 34 are defined by anouter circumferential surface of the pump rotor 31, the cam face of thecam ring 33, and adjacent vanes 32.

The cam ring 33 is an annular member having the substantially ovalshaped cam face with a minor axis and a major axis. The cam face of thecam ring 33 has two suction regions in which volumes of the pumpchambers 34 are increased with the rotation of the pump rotor 31 and twodischarge regions in which the volumes of the pump chambers 34 aredecreased with the rotation of the pump rotor 31.

A first side plate 36 is arranged so as to be in contact with one sidesurfaces of the pump rotor 31 and the cam ring 33, and a second sideplate 37 is arranged so as to be in contact with the other side surfacesof the pump rotor 31 and the cam ring 33. As described above, the firstside plate 36 and the second side plate 37 are arranged so as tosandwich the pump rotor 31 and the cam ring 33 from both sides thereof,and thereby, the pump chambers 34 are defined.

The first side plate 36 is arranged between the pump rotor 31 and abottom surface 40 b of the pump housing 40. The second side plate 37 isarranged between the pump rotor 31 and the motor cover 3 b.

The pump rotor 31, the cam ring 33, the first side plate 36, and thesecond side plate 37 are accommodated in a pump accommodating portion 40a that is formed in the pump housing 40 so as to have a recessed shape.The pump housing 40 and the motor cover 3 b are fastened together withbolts, and an opening portion of the pump accommodating portion 40 a isclosed the motor cover 3 b of the motor housing 3.

The first side plate 36 is a disc-shaped member, and has two arc-shapeddischarge ports 36 a that are formed so as to penetrate through thefirst side plate 36. The discharge ports 36 a open so as to correspondto the discharge regions of the cam ring 33, and discharge the workingoil in the pump chambers 34.

A projection 50, which is inserted into the through hole 31 a of thepump rotor 31, is formed on the first side plate 36 so as to be integralwith the first side plate 36. The projection 50 is formed so as toproject from the center portion of a side surface of the first sideplate 36 and so as to have a cylinder shape concentric with the throughhole 31 a of the pump rotor 31. A gap is formed between an outercircumferential surface 50 a of the projection 50 and the innercircumferential surface of the through hole 31 a, and a gap is alsoformed between an end surface 50 b of the projection 50 and an endsurface 4 b of the driving shaft 4. In other words, when the drivingshaft 4 and the pump rotor 31 are rotated, the projection 50 does notcome into contact with the driving shaft 4 and the pump rotor 31. Afunction of the projection 50 will be described later in detail.

The second side plate 37 is an annular member, and a through hole 37 a,through which the driving shaft 4 is inserted, is formed at the centerportion of the second side plate 37 so as to penetrate therethrough inthe axial direction. In addition, two ark-shaped suction ports (notshown) are formed by being cut out in an outer circumference of thesecond side plate 37. The two suction ports open so as to correspond tothe two suction regions of the cam ring 33, and guide the working oil tothe pump chambers 34. The second side plate 37 is not essential to theconfiguration of the vane pump 100, and it may be possible to omit thesecond side plate 37. In such a case, the pump rotor 31 and the cam ring33 are sandwiched by the first side plate 36 and the motor cover 3 bfrom both sides, and thereby, the pump chambers 34 are defined.

Relative rotation between the cam ring 33, the first side plate 36, andthe second side plate 37 is restricted by two positioning pins 46. Withsuch a configuration, the suction regions of the cam ring 33 and thesuction ports of the second side plate 37 are aligned, and the dischargeregions of the cam ring 33 and the discharge ports 36 a of the firstside plate 36 are aligned.

The positioning pins 46 are inserted through the cam ring 33 and thesecond side plate 37 such that one end sides thereof are inserted intopositioning holes 36 d that are formed in the first side plate 36 andthe other end sides thereof are inserted into positioning holes 3 e thatare formed in the motor cover 3 b. As described above, the cam ring 33,the first side plate 36, and the second side plate 37 are aligned by thepositioning pins 46 with respect to the motor cover 3 b.

An inner circumferential surface of the hollow portion 3 d of the motorcover 3 b is provided with a seal member 45 with which an outercircumferential surface of the driving shaft 4 is in sliding contact.Leakage of the working oil from the vane pump 100 to the electric motor1 is prevented by the seal member 45.

An annular high-pressure chamber 42 that communicates with the dischargeports 36 a of the first side plate 36 is formed in the bottom surface 40b of the pump accommodating portion 40 a. The high-pressure chamber 42is defined by the first side plate 36 that is arranged on the bottomsurface 40 b of the pump accommodating portion 40 a. The high-pressurechamber 42 communicates with a discharge passage 41 that is formed so asto open at an outer surface of the pump housing 40.

A suction passage (not shown) that communicates with the suction portsof the second side plate 37 is also formed in the pump housing 40. Thesuction passage communicates with a tank that stores the working oil.

As the driving shaft 4 is rotated by driving the electric motor 1, thepump rotor 31 coupled to the driving shaft 4 is rotated, and thereby,the respective pump chambers 34 in the cam ring 33 suck the working oilthrough the suction ports of the second side plate 37 and discharge theworking oil to the high-pressure chamber 42 through the discharge ports36 a of the first side plate 36. The working oil in the high-pressurechamber 42 is supplied to a hydraulic apparatus through the dischargepassage 41. As described above, the respective pump chambers 34 in thecam ring 33 suck and discharge the working oil by expansion andcontraction caused by the rotation of the pump rotor 31.

Next, a method for assembling the electric motor 1 and the vane pump 100will be described.

Production is performed by assembling the electric motor 1 and the vanepump 100 after the electric motor 1 and the vane pump 100 are fabricatedseparately. FIG. 2 is a diagram showing a state before the electricmotor 1 and the vane pump 100 are assembled. As shown in FIG. 2, adescription will be given of a case in which the electric motor 1 andthe vane pump 100 are assembled in a state where the driving shaft 4 ofthe electric motor 1 is orientated perpendicular to the verticaldirection.

The assembly of the electric motor 1 and the vane pump 100 is performedby inserting the driving shaft 4 of the electric motor 1 into thethrough hole 31 a of the pump rotor 31 of the vane pump 100, insertingthe positioning pins 46 of the vane pump 100 into the positioning holes3 e of the motor cover 3 b, and thereafter, fastening the pump housing40 and the motor cover 3 b with bolts. A detailed described is givenbelow.

Before describing the method of assembling the electric motor 1 and thevane pump 100 according to this embodiment, problems associated with theassembly will be described.

In the vane pump 100, before the electric motor 1 and the vane pump 100are assembled, the pump rotor 31 is not fixed and is in a freely movablestate in the cam ring 33, and so, the pump rotor 31 falls into a bottomportion in the cam ring 33 due to gravity. In this case, the pump rotor31 moves in the vertical direction relative to the second side plate 37,and the position of the through hole 31 a of the pump rotor 31 isdeviated from the position of the through hole 37 a of the second sideplate 37. Thus, a state in which a part of the through hole 37 a of thesecond side plate 37 is blocked by the side surface of the pump rotor 31is brought about. In such a case, even when the driving shaft 4 is to beinserted through the through hole 37 a of the second side plate 37 andinserted into the through hole 31 a of the pump rotor 31, because theend surface 4 b of the driving shaft 4 interferes with the side surfaceof the pump rotor 31, it becomes difficult to insert the driving shaft 4into the through hole 31 a of the pump rotor 31. As described above, anoperation of inserting the driving shaft 4 into the through hole 31 a ofthe pump rotor 31 becomes complicated. Especially, in a case in whichthe electric motor 1 and the vane pump 100 are assembled in a statewhere the diameter of the pump rotor 31 is orientated so as to coincidewith the vertical direction, because the position of the through hole 31a of the pump rotor 31 deviates greatly from the position of the throughhole 37 a of the second side plate 37, the operation of inserting thedriving shaft 4 into the through hole 31 a of the pump rotor 31 becomesfurther complicated.

As a countermeasure against this problem, in this embodiment, the firstside plate 36 of the vane pump 100 is formed with the projection 50 thatis to be inserted into the through hole 31 a of the pump rotor 31. Withsuch a configuration, as shown in FIG. 2, in a state before the electricmotor 1 and the vane pump 100 are assembled, the inner circumferentialsurface of the through hole 31 a of the pump rotor 31 is brought intocontact with the outer circumferential surface 50 a of the projection50, and thereby, the pump rotor 31 is supported by the projection 50 torestrict the fall of the pump rotor 31 in the cam ring 33. Therefore,the positional deviation between the through hole 31 a of the pump rotor31 and the through hole 37 a of the second side plate 37 becomes small.Specifically, the positional deviation between the through hole 31 a ofthe pump rotor 31 and the through hole 37 a of the second side plate 37corresponds to the gap between the outer circumferential surface 50 a ofthe projection 50 and the inner circumferential surface of the throughhole 31 a in a state in which the electric motor 1 and the vane pump 100are assembled (the state shown in FIG. 1).

In a state in which the pump rotor 31 is supported by the projection 50,as the driving shaft 4 is inserted through the through hole 37 a of thesecond side plate 37 and inserted into the through hole 31 a of the pumprotor 31, a tapered surface 4 c formed on an outer circumference edge ofthe end surface 4 b of the driving shaft 4 is brought into contact withan inner circumference edge 31 c of the through hole 31 a of the pumprotor 31, thereby lifting the pump rotor 31 upwards. Thus, the malespline 4 a of the driving shaft 4 enters inside the female spline 31 b,and connection between the male spline 4 a and the female spline 31 b isachieved.

In a state in which the male spline 4 a is connected to the femalespline 31 b, in other words, in a state in which the driving shaft 4 iscoupled to the pump rotor 31, as shown in FIG. 1, the projection 50 isarranged concentrically with the through hole 31 a of the pump rotor 31,and the gap is formed between the outer circumferential surface 50 a ofthe projection 50 and the inner circumferential surface of the throughhole 31 a. In addition, the gap is also formed between the end surface50 b of the projection 50 and the end surface 4 b of the driving shaft4. Therefore, when the driving shaft 4 and the pump rotor 31 arerotated, the projection 50 does not interfere with the driving shaft 4and the pump rotor 31.

As described above, the projection 50 has a function of aligning thepump rotor 31 in the cam ring 33 and facilitating the insertion of thedriving shaft 4 into the through hole 31 a when the driving shaft 4 isinserted into the through hole 31 a of the pump rotor 31.

According to the above-described first embodiment, the advantagesdescribed below are afforded.

Because the first side plate 36 is formed with the projection 50 that isto be inserted into the through hole 31 a of the pump rotor 31, duringthe assembly of the electric motor 1 and the vane pump 100, the pumprotor 31 is aligned in the cam ring 33 by the projection 50 when thedriving shaft 4 is inserted into the through hole 31 a of the pump rotor31. Thus, the centers of the pump rotor 31 and the cam ring 33 areprevented from being deviated greatly, and thereby, it is possible toimprove the assemblability of the vane pump 100.

A modification of the first embodiment will be described below.

(1) In the above-mentioned embodiment, a description has been given ofthe configuration in which the projection 50 is formed integrally withthe first side plate 36. Instead of this configuration, as shown in FIG.3, the projection 50 may be formed separately from the first side plate36. Specifically, the cylinder-shaped projection 50 may be press-fittedinto a groove 36 b formed in the side surface of the first side plate36.

The side surface of the first side plate 36 on which the pump rotor 31slides needs to be polished in order to improve sliding property of thepump rotor 31. In a case in which the projection 50 is formed integrallywith the first side plate 36, it is difficult to perform this polishingoperation. However, in a case in which the projection 50 is formedseparately from the first side plate 36, because the first side plate 36can be polished before press-fitting the projection 50 into the groove36 b of the first side plate 36, workability of the polishing operationis improved.

(2) In the above-mentioned embodiment, a description has been given ofthe configuration in which the projection 50 is formed so as to projectfrom the center portion of the side surface of the first side plate 36and so as to have a cylinder shape concentric with the through hole 31 aof the pump rotor 31. Instead of the projection 50, as shown in FIG. 4,a plurality of cylinder shaped projections 51 may be formed on the sidesurface of the first side plate 36. FIG. 4 is a side view of the firstside plate 36 viewed from the pump rotor 31 side. Three projections 51are formed at 120 degree intervals on the same circle.

In a state in which the driving shaft 4 and the pump rotor 31 arecoupled, there are gaps between outer circumferential surfaces ofrespective projections 51 and the inner circumferential surface of thethrough hole 31 a of the pump rotor 31. In addition, in a state beforethe electric motor 1 and the vane pump 100 are assembled, the innercircumferential surface of the through hole 31 a of the pump rotor 31 isbrought into contact with any of the outer circumferential surfaces ofthe projections 51, and thereby, the pump rotor 31 is supported by theprojections 51.

If an attaching orientation of the vane pump 100 is fixed in advance, itmay be possible to provide only one projection 51 on the vertical line.

(3) The configuration is not limited to that in which the driving shaft4 is rotated by the motive force from the electric motor 1. For example,a configuration in which the driving shaft 4 is rotated by a motiveforce from an engine may also be possible. In other words, the vane pump100 is not limited to the configuration in which the vane pump 100 isassembled with the electric motor 1.

Second Embodiment

A vane pump 200 according to a second embodiment of the presentinvention will be described with reference to FIG. 5. In the followingdescription, differences from the above-described first embodiment willbe mainly described, and components that are the same as those in thevane pump 100 according to the above-described first embodiment areassigned the same reference numerals and descriptions thereof will beomitted. In FIG. 5, illustration of the electric motor 1 is omitted.

In contrast to the vane pump 100 according to the above-described firstembodiment in which the first side plate 36 is formed with theprojection 50 that is inserted into the through hole 31 a of the pumprotor 31, in the vane pump 200, a projection 60 that is to be insertedinto the through hole 31 a of the pump rotor 31 is formed on the pumphousing 40. The detail of the embodiment will be described below.

The projection 60 is formed integrally with the pump housing 40 so as toproject from the center portion of the bottom surface 40 b of the pumphousing 40. In a state in which the driving shaft 4 and the pump rotor31 are coupled, the projection 60 is formed so as to be inserted througha through hole 36 c formed in the first side plate 36 and so as to havea cylinder shape concentric with the through hole 31 a of the pump rotor31. A gap is formed between an outer circumferential surface 60 a of theprojection 60 and the inner circumferential surface of the through hole31 a, and a gap is also formed between an end surface 60 b of theprojection 60 and the end surface 4 b of the driving shaft 4. In otherwords, when the driving shaft 4 and the pump rotor 31 are rotated, theprojection 60 does not come into contact with the driving shaft 4 andthe pump rotor 31.

The projection 60 may be formed separately from the pump housing 40 andmay be press-fitted into a groove formed in the bottom surface 40 b ofthe pump housing 40.

In order to prevent a leakage of the working oil in the high-pressurechamber 42 from between the outer circumferential surface 60 a of theprojection 60 and the through hole 36 c of the first side plate 36, aseal member 61 is provided between the bottom surface 40 b of the pumphousing 40 and the first side plate 36 so as to surround an outercircumference of the projection 60.

Also with the above-described second embodiment, the operationaladvantages similar to those in the above-described first embodiment areafforded.

The configurations, operations, and effects of the embodiment accordingto the present invention will be collectively described below.

The vane pump (100, 200) includes: the pump rotor 31 having the throughhole 31 a to which the driving shaft 4 is coupled; the plurality ofvanes 32 provided so as to be freely reciprocatable in the radialdirection with respect to the pump rotor 31; the cam ring 33 configuredto accommodate the pump rotor 31, the cam ring 33 being configured suchthat the tip-ends of the vanes 32 slide on the inner circumferentialsurface of the cam ring 33 as the pump rotor 31 is rotated; the pumphousing 40 configured to accommodate the pump rotor 31 and the cam ring33; and the first side plate 36 provided between the pump rotor 31 andthe bottom surface 40 b of the pump housing 40, wherein the first sideplate 36 or the pump housing 40 is formed with the projection (50, 60),the projection (50, 60) being inserted into the through hole 31 a of thepump rotor 31.

With this configuration, because the projection (50, 60), which is to beinserted into the through hole 31 a of the pump rotor 31, is formed onthe first side plate 36 or the pump housing 40, when the driving shaft 4is inserted into the through hole 31 a of the pump rotor 31, the pumprotor 31 is aligned in the cam ring 33 by the projection (50, 60). Thus,the centers of the pump rotor 31 and the cam ring 33 are prevented frombeing deviated greatly, and thereby, it is possible to improve theassemblability of the vane pump (100, 200).

In addition, the projection (50, 60) is configured such that the pumprotor 31 is aligned in the cam ring 33 when the driving shaft 4 isinserted into the through hole 31 a of the pump rotor 31.

In addition, the projection 50 is formed to have a cylinder shapeconcentric with the through hole 31 a of the pump rotor 31, and a gap isformed between the outer circumferential surface 50 a of the projection50 and the inner circumferential surface of the through hole 31 a, and agap is formed between the end surface 50 b of the projection 50 and anend surface 4 b of the driving shaft 4.

With this configuration, when the driving shaft 4 and the pump rotor 31are rotated, the projection 50 does not interfere with the driving shaft4 and/or the pump rotor 31.

In addition, the projection 50 is press-fitted into the groove 36 bformed in the side surface of the first side plate 36.

With this configuration, because the projection 50 is formed separatelyfrom the first side plate 36, the first side plate 36 can be polishedbefore the projection 50 is press-fitted into the groove 36 b of thefirst side plate 36, and therefore, workability of the polishingoperation is improved.

In addition, the projection 60 is provided so as to project from thebottom surface 40 b of the pump housing 40 and so as to be insertedthrough the through hole 36 c formed in the first side plate 36.

Embodiments of this invention were described above, but the aboveembodiments are merely examples of applications of this invention, andthe technical scope of this invention is not limited to the specificconstitutions of the above embodiments.

This application claims priority based on Japanese Patent ApplicationNo. 2016-225216 filed with the Japan Patent Office on Nov. 18, 2016, theentire contents of which are incorporated into this specification.

1. A vane pump comprising: a rotor having a through hole to which adriving shaft is coupled; a plurality of vanes provided so as to befreely reciprocatable in a radial direction with respect to the rotor; acam ring configured to accommodate the rotor, the cam ring beingconfigured such that tip-ends of the vanes slide on an innercircumferential surface of the cam ring as the rotor is rotated; ahousing configured to accommodate the rotor and the cam ring; and a sideplate provided between the rotor and a bottom surface of the housing,wherein the side plate or the housing is formed with a projection, theprojection being inserted into the through hole of the rotor, and theprojection is press-fitted into a groove formed in a side surface of theside plate.
 2. The vane pump according to claim 1, wherein theprojection is configured such that the rotor is aligned in the cam ringwhen the driving shaft is inserted into the through hole of the rotor.3. The vane pump according to claim 1, wherein the projection is formedto have a cylinder shape concentric with the through hole of the rotor,and a gap is formed between an outer circumferential surface of theprojection and an inner circumferential surface of the through hole, anda gap is formed between an end surface of the projection and an endsurface of the driving shaft.
 4. (canceled)
 5. (canceled)